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C. H. POND 8L H. L. BAILEY.

ELECTRIC GLOGK.

Patented Deo. 2, 1884.

INVENTORS (/zeSZelHfonZ,

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UNITED STATES PATENT OFFICE.

CHESTER H. POND, OE NEV YORK, AND HENRY L. BAILEY, OF BROOKLYN, ASSIGNORS TO THE TIME TELEGRAPH COMPANY, OE NEV YORK, N. Y.

ELECTRIC CLOCK.

v SPECIFICATION forming part of Letters Patent No. 308,793, dated December 2, 1884:.

Application filed September 5, 1883. (No model.)

To all 'whom it may concern:

Be it known that we, GIIEsTEE H. POND and HENRY L. BAILEY, citizens of the United States, residing, respectively, in the city of 5 New York, in the county and State of New York, and in Brooklymiu the county of Kings and State of New York, have jointly invented certain new and useful Improvements in Electric Clocks, of which the following is a specifi- Io cation.

Our invention relates to certain improve Inents in the construction and organization oi' self-propelling electric clocks.

The object of the invention is to provide a clock the operation of which is effected by the agency of electric currents automatically caused to vitalize in alternation two sets of electro-magnets, which magnets are adapted to control suitable mechanism for imparting 2Q a slight impulse to the pendulum at each semivibration of the same, and also to construct the contact-points through which the electric circuits are completed and interrupted in such a manner as to especially adapt them to this use.

rlhe invention consists in securing to a vibrating pendulum a bracket supporting two contaet-points, respectively adapted to make complete and electrical connections through a 3o corresponding electro-magnet when near its limit of oscillation, thereby causing the magnet to be vitalized and a resilient arm to be released. This arm acts, by pressing against the contact-point, to impel the pendulum in the opposite direction. IVhcn the pendulum has swung to the opposite limit of its vibration, a similar operation takes place, and another impulse tending to Vreverse the direction of the pendulum is communicated to it. The 4o contactpoints through which the circuit is closed are in the Lli'orm of two knife-edges intersecting each other at au angle, and the points from which the arms are supported are so located that the movement of the contactpoints, caused by the vibration of the pendulum, will cause the knife-edges to rub slightly across each other, thereby keeping the surfaces free from dust and corrosion.

In a patent of A. G. Crane, No. 301,569,

dated July 8, 1884, there is shown and claimed an electro-magnetic clock in which a pair of electro-magnets have their respective armatures mounted upon a lever common to both. Each armature carries a contact-iinger arranged to uphold a corresponding spring, except when the spring is raised. by arms carried by the pendulum. A circuit is completed through the respective electro-magnets by the contact of the respective contact-lingers with the resilient arms or springs, The swing of the pendulum interrupts such circuit and causes the contact-ii1igeito be withdrawn from the path oi the spring, and the latter then follows the arm carried by the pendulum, exerting upon it a pressure. The pressure thus alternately given to the pendulum by the two springs maintains itin motion. Such an organization as this we make no claim to. Our organization differs therefrom fundamentally in the method oi' controlling the circuit-connections, and in the movements of the arms or fingers employed for raising the springs. According to our organization, the circuit is through the contactpoints carried by the pendulum. The armature-lever is employed ior raising the springs, but immediately upon the completion of one or the other circuit the corresponding iinger is withdrawn. This con` struction also involves a dilierence in the organization of circuits, as will hereinafter appear.

III the accompanying drawings, Figure l I shows in elevation such parts of an electric clock as will suliice to illustrate our invention, and Eig. 2 is a detached view showing the construction of the contact-points.

Referring to the drawings, A represents a pendulum of any suitable form, preferably suspended by means of a ilexiblc strip of metal, B, secured to the frame or support O. Upon the pendulum A is fixed a bracket, l), having two arms, d and di, respectively projecting from opposite sides of the same. Two contact-points, d and (V, are respectively carried at the extremities of the arms d and di, and these points are rendered adjustable by being mounted upon adjusting-screws di and df. Check-nuts d7 and di, each of which is insertcd in a fork at the end of the correspondf ing arm, d or d2, serve to raise or lower the contact-points by turning upon the screw-thread. For the purpose of furtherpreventing any lateral movement of the contact-points two setscrews, dn and dm, are provided for binding against the side of the same. Above the arms d and d2 extend two resilient arms or springs, c and c?, secured to but insulated from the frame C. Two contact-points, cia and c, are respectively carried at the extremities of these arms, and are designed to make contact with the corresponding` points, d3 and d", near the respective limits of the vibration of the pendulum A. The contact-surfaces of the points are constructed in the form of prisms or knife-edges, as more clearly shown in the detached view Fig. 2, and these are so placed that their planes will intersect each other at an angle, preferably a right angle. The contacts may be constructed of tempered steel, platinum, or other suitable metal, the essential point being that the surfaces which come in contact with each other shall be sharp, the general form of the points being that of a wedge or prism.

Secured to the frame C is a bracket, F, upon which is pivoted a table or rocking sup` port, H, having its center of oscillation in the same vertical line with the support of the pendulum A, but preferably in a lower horizontal plane. Near the respective extremities of the table H are carried two upwardlyprojecting arms, 7i. and 7a2, respectively designed to raise the correspondingspring, e or c2, whenever the corresponding end ei' the table is raised. In the drawings we have represented the table as in a horizontal position, both springs being slightly raised by the arms h and lr. If, however, the left-hand end of the table, for instance, be depressed, the spring c will be still further raised, while the spring c`l will be allowed to fall, which it will do by virtue oi" its resilience. The table H is designed to be so oscilla-ted that the springs or resilient arms c and c`l will in this manner be alternately raised by means of the corresponding arms, 71./ and 7i?, when the pendulum is near one limit or the other of its vibration. The remaining spring will at the same time be released and impart an impulse to the pendulum by virtue of the pressure exerted through the contact-points.

Two electro-magnets, M and M2, are provided for tilting the table H alternately in one direction or the other by acting upon two armatures, m and m2, respectively, attached to the opposite extremities of the table. @ne pole of a battery, 0, is connected through a conductor, l, with the frame C of the clock, and thus with the bracket D and contactpoints d and d. The opposite pole of the battery O is connected through conductors 2, 3, and 4 with the outer terminals of the coils of the electromagnets M and M2, respectively, while the inner terminals of these coils are connected through conductors 5 and 6 with the resilient arms c and c, and thus with the contact-points ci" and c", respectively. lt will be understood, therefore, that when the contact-point di", for instance, is carried by the movement ofthe pendulum toward the right hand against the contact-point c" the circuit of the battery O will be completed through conductors 2 and 3, coils ol the electro-magnet lll', conductor 5, resilient arm c, contact-points c and d5", bracket D, supportiiig-spring B, frame C, and conductor l.. The electro-magnet M will thus be vitalized and the right-hand end of the table H will be drawn downward, thereby releasingthe resilient arm c',- hence the arm c will exertapressure upon the arm d/through the contact-points c: and d". The pendulum willbe causcdto swingtoward the left hand not only by the action of gravity, but also under the inliuence of the additional force exerted by the tension ofthe spring c. The resilient arm or spring c will continue to exert the pressure until it is arrested by striking against the arm '/i. The further movement of the pendulum by virtue o'lV- its acquired momentum will cause the separation of the contactpoints ci and di", thus interrupting the circuit ofthe battery O through the electro-magnet MC The point d will, however, be carried into contact with the point c, thereby completing the circuit oi' the battery O through the conductors 2 and 4, coils of the electro-magnet Mt, conductor 6,contact-pointscl and d,bracket D, and conductor l. The electro-magnet M2 will thereupon be v'italized and the left-hand end ofthe table H will be drawn downward, releasing the spring` c2, which will add animpulse to the pendulum A, tending to again vibrate it toward the right hand in precisely the same manner as already described with reference to the spring c. This operation will be repeated Vfor each semi-vibration of the pendulum.

It is evident that the circuit through one electro-magnet may be completed immediately before that through the other is interrupted, or immediately thereafter; or the completion of one may be simultaneous with the interruption ofthe other circuit. In practice, however, we prefer the latter arrangement.

lt is well known that alter the vibration ol' a pendulum has been established a very slight force or series of impulses contini'iously imparted thereto will. be sufficient to maintain that vibration, and for this reason it is only necessary that the springs c and cIl should exert a very slight pressure.

For the purpose ot preventing the occurrence ol'electrieal discharges at the contactpoints when the circuit is interrupted,we cmploy two shunt-circuits, 7 and 8, respectively extending around the coils of the electro-magnet M and M2, and including artificial resistances r and frf, The resistance of each of these circuits should be sufficiently great to prevent the passage ol" any considerable current therethrough, but not so great as to pre- IOO vent the eXtra or induced currents,which are caused by the discharge of the electro-magnets, from passing therethrough, in preference to establishing arcs between the separating contact-points, and thereby oxidizing or burning them away.

XVe claim as our inventionl. rlhe combination, substantially as hereinbefore set forth, of two electro-magnets, their armatures respectively supported upon opposite extremities of a centrally-pivoted lever, a vibrating pendulum, two prisniatic contact-points respectively supported from opposite sides of said pendulum, two resilient arms, two prisinatic contact-points respectively supported upon the extremities of said resilient arms in planes intersecting the planes of the iirst -named contact points, a battery, conductors connecting one pole of said battery with one pair of said contact-points through the coils .of said electro-magnets, and conductors connecting the remaining pair of contact-points with the remaining pole of said battery.

2. The combination, substantially as hercinbefore set forth, with a clock-pendulum, of two electro-magnets, an armature-lever, two armatures attached thereto and applied to said electro magnets, respectively, two contact-points moving with said pendulum, two impulse-springs, and lifting-fingers applied to said springs and carried upon said armaturelcver, each of which springs is adapted to\ close a circuit through the corresponding electro-magnet when, by the swing of the pendulum, it is touched by the corresponding contact-point, whereby through the attraction ot' thc armature the litting-iinger is withdrawn and the spring permitted to act so as to give an impulse to the pendulum.

The combination, substantially as hereinbefore set i'orth, with a clock-pendulum, of two electro-magnets, two resilient arms, knifeedge contacts carried thereon ,respeetivcly,two knife-edge contacts moving with said pendulum and applied to the first-named contacts, respectively, two armatures applied to said electro-magnets,respectively, two lifting-arms respectively moving with said armatures and applied to said resilient arms, and electrical connections, substantially as described, from said contacts through said electro-magnets, whereby one or the other electro-magnet is vitalized when the swing of the pendulum has carried one or the other of the contacts moving therewith against the corresponding contact.

In testimony whereof we have hereunto subscribed onr names this 4th day ol September, A. D. 1883.

CHESTER H. POND. HENRY L. BAILEY.

W'itnesses:

DiiXinL XV. EDGncoMn, (Ji-Linus A. TERRY. 

